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Microwave Week, as it was billed by the IEEE this past June 1-6 in Tampa, Fla., turned out to be more than just time on the beach and a mid-year break from the factory. This year’s Microwave Theory & Techniques Society (MTT-S) International Microwave Symposium (IMS 2014) was a well-attended conference and exhibition, with more than 150 technical presentations and demonstrations, and more than 550 exhibition booths for visitors to sample the newest RF/microwave offerings.

As it is year after year, the exhibition floor was truly an opportunity for RF/microwave specifiers to learn about existing and new products at every level, from tiny devices to massive systems. Perhaps even more invaluable than the opportunity to see the products was the chance to meet many of the engineers behind them, picking their brains for modifications, enhancements, and improvements.

For those in need of increased functionality in smaller-sized packages, and to generate clean output signals, IMS 2014 offered the opportunity to collect data on some tremendous offerings in new integrated-circuit (IC) products. Among these were the model LMX2492 14-GHz fractional-N Platinum phased-locked-loop (PLL) IC from Texas Instruments. This device (Fig. 1) supports a 200-MHz phase frequency detector, a 5-V charge pump supply, and an operating frequency range of 0.5 to 14.0 GHz. The company offered the IC and guidance on its use in Tampa.

Fractional-N frequency-synthesizer chip

Available in industrial and automotive grade packaging, in a 24-pin, 4-×-4 mm WQFN housing, the PLL exhibits a phase-noise floor of -227 dBc/Hz in support of low-noise local oscillators (LOs) for enhanced receiver sensitivity. The wide modulation bandwidth enables flexible frequency and phase modulation, including linear frequency modulation (FM), frequency-shift-keying (FSK) modulation, and phase-shift-keying (PSK) modulation.

With the aid of Texas Instruments’ WEBENCH Clock Architect software (which features more than 40,000 component models from suppliers in addition to Texas Instruments), engineers can simulate different oscillators and timing schemes. The software includes a PLL loop-filter design section that allows optimization of phase noise and jitter for different oscillator designs. The company also had its model LMX2492EVM evaluation module (EVM) on display at the exhibition, to show designers a quick and easy way to get started designing oscillator and synthesizer circuits with the LMX2492.

Also at IMS 2014 to help exhibition visitors achieve precise signal generation, CTS Corp. showed off its model 149 oven-controlled crystal oscillator (OCXO) from subsidiary CTS Electronic Components, Inc. Designed for high stability in a miniature package, the OCXO was being offered in frequencies from 10 to 25 MHz with stability as tight as ±50 ppb for a wide temperature range of -40 to +85°C. This type of oscillator, with phase noise of only -152 dBc/Hz offset 100 kHz from the carrier, would normally be considerably larger than the circuit in this package, which measures only 9 × 14 mm.

But many of the visitors to the CTS booth might even have questioned whether this was truly an oven-controlled oscillator in that small package, until they saw the stability performance. The bonus is that at room temperature (+25°C), this tiny oscillator consumes less than 1 W of power from a +3.3 or +5.0 VDC voltage supply.

One of several trends among component suppliers at IMS 2014 was the growing availability of millimeter-wave products, notably for areas of interest like line-of-sight communications links and automotive radar systems. For example, MACOM Technology Solutions unveiled its broadband model MAAP-011106 power amplifier (PA), designed for use at E-band frequencies from 71 to 86 GHz (Fig. 2). Suited for use in small-cell wireless backhaul equipment, the E-band amplifier supports wireless data rates to 1 Gb/s and higher at those frequencies with saturated output-power levels of +25.5 dBm in the standard 71-to-76-GHz and 81-to-86-GHz millimeter-wave communications bands normally handled by two separate amplifiers.

MACOM single amplifier

The E-band PA is based on GaAs pseudomorphic-high-electron-mobility-transistor (pHEMT) monolithic-microwave-integrated-circuit (MMIC) semiconductor technology. It features an integrated power detector and provides 20-dB small-signal gain with variable gain control for flexible performance tuning. The amplifier is rated for saturated output power of +25 dBm from 71 to 86 GHz, with an output third-order intercept point (OIP3) of +30 dBm or more.

Skyworks Solutions made noise at the 2014 IMS for its lack of noise—or more specifically, a number of new low-noise amplifiers (LNAs) with impressive noise-figure performance. As examples, amplifier models SKY67150-396LF and SKY67153-396LF were designed and optimized for applications from 300 to 2200 MHz and from 700 to 3800 MHz, respectively, with healthy small-signal gain and extremely low noise figures. Suitable for controlling noise in receivers (especially in commercial wireless communications systems), the amplifiers take advantage of a GaAs pHEMT semiconductor process and proven packaging methods to do away with noise.

Supplied in a 2-×-2 mm, 8-pin dual flat no lead (DFN) package, model SKY67150-396LF operates from 300 to 2200 MHz and achieves a typical minimum noise figure of just 0.23 dB when tested in the firm’s evaluation board at 849 MHz; the maximum noise figure is 0.38 dB at that test frequency and in the evaluation board. For additional measurements referenced to a test frequency of 849 MHz in the evaluation board, the LNA provides 19.0 dB minimum small-signal gain and 20.5 dB typical small-signal gain, with typical input return loss of 11 dB and typical output return loss of 20 dB. In the same evaluation board, the typical 1-dB input compression point is +1.5 dBm at 849 MHz and the typical 1-dB output compression point is +21 dBm at 849 MHz. The amplifier offers a typical third-order output intercept pint of +39 dBm at 849 MHz.

What makes this amplifier so interesting—and versatile—is that it can be used over a range of bias voltages (+3 to +5 VDC) and a wide range of adjustable supply currents (from 20 to 100 mA). It can be used at frequencies as low as 100 MHz with high gain and low noise figure and with degraded input return loss. The model SKY67153-396LF LNA offers outstanding noise figure and similar performance across the higher frequency range, making it well suited for wireless communications infrastructure applications.

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